command: Remove the cmd_tbl_t typedef

We should not use typedefs in U-Boot. They cannot be used as forward
declarations which means that header files must include the full header to
access them.

Drop the typedef and rename the struct to remove the _s suffix which is
now not useful.

This requires quite a few header-file additions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/arm926ejs/mxs/mxs.c b/arch/arm/cpu/arm926ejs/mxs/mxs.c
index 7298841..d742c0f 100644
--- a/arch/arm/cpu/arm926ejs/mxs/mxs.c
+++ b/arch/arm/cpu/arm926ejs/mxs/mxs.c
@@ -10,6 +10,7 @@
  */
 
 #include <common.h>
+#include <command.h>
 #include <cpu_func.h>
 #include <hang.h>
 #include <init.h>
@@ -187,7 +188,8 @@
 }
 #endif
 
-int do_mx28_showclocks(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
+int do_mx28_showclocks(struct cmd_tbl *cmdtp, int flag, int argc,
+		       char *const argv[])
 {
 	printf("CPU:   %3d MHz\n", mxc_get_clock(MXC_ARM_CLK) / 1000000);
 	printf("BUS:   %3d MHz\n", mxc_get_clock(MXC_AHB_CLK) / 1000000);